A combustor, for example a reheat combustor, in a gas turbine engine may typically comprise the arrangement shown in FIG. 1. The combustor may comprise one or more gutters 10, which create a stagnation zone 12 in the flow 11. The gutters 10 may enable the flow to have a large residence time in the low velocity stagnation zone 12. Combustion may occur under such conditions because the rate of mixing (eg due to turbulent eddies) is low. The combustion reaction may then propagate downstream to the surrounding flow 14 by diffusion. Combustion is therefore created in a low velocity area that propagates in the flow and the combustion sustained and protected from extinction by the gutter.
However, a disadvantage of the prior art arrangement shown in FIG. 1 is that a spark or a fuel plug (not shown) is required to ignite the combustion. An electrical system or a burning plug of fuel is thus required and such systems add undesirable complexity.
A further problem with the prior art arrangement is the high drag introduced by the gutters in a region where the pressure losses must be minimised. For example, pressure losses in the reheat section have an adverse effect on the thrust and/or efficiency. Pressure losses are already introduced by reheating the flow, so it is desirable to avoid further pressure losses.
The present disclosure therefore seeks to address these issues.